Allium ursinum: botanical, phytochemical and pharmacological overview

Danuta Sobolewska 0 Irma Podolak 0 Justyna Makowska-Was 0 0 D. Sobolewska (&) I. Podolak J. Makowska-Was Department of Pharmacognosy, Jagiellonian University, Medical College , 9 Medyczna Street, Krakow, Poland RamsonAllium ursinum L. is a medicinal and dietary plant species with a long tradition of use. This mini-review summarizes the current knowledge on the phytochemistry and pharmacological properties of this valuable plant, with special emphasis on antimicrobial, cytotoxic, antioxidant, and cardioprotective effects. - Allium ursinum L. has been used for centuries in traditional medicine. However, studies on its composition and pharmacological activity are fairly recent and scarce. The aim of the present review was to summarize the most important aspects related to A. ursinum and provide an outline of phytochemical and pharmacological properties of this relatively poorly known plant species of the Allium genus. The species name ursinum is of Latin origin, being derived from ursus (bear), and is related to folk tales, according to which bears after awakening from winter hibernation consume this plant to remove toxins from the body and to regain strength (Rejewski 1996). Another etymological hypothesis refers to the Ursa major, a constellation in the northern hemisphere, perhaps because A. ursinum was, to ancient Greeks especially, one of the most northerly distributed Allium species (Bohling 2008). Contemporary systematics places this plant in the family Amaryllidaceae (previously in Alliaceae), subgenus Amerallium Traub, section Arctoprasum Kirschl. (Friesen et al. 2006; Chase et al. 2009; Govaerts 2011). Several synonyms are recognized: Allium nemorale Salisb., A. latifolium Gilib., and Ophioscorodon ursinum (L.) Wallr. Thanks to its wide-spread distribution and popularity as edible and medicinal plant, most modern European languages have common names for A. ursinum which are used interchangeably. These are: Ramson or Bears garlic (English); Barlauch (German); Ail des ours, Ail sauvage (French); Kyr velde;bq, Xecyor velde;bq or Xepevia (Russian); Ramslo k (Swedish); Daslook (Dutch); Czosnek niedzwiedzi (Polish). Also, the name wild garlic is very often used in literature with respect to A. ursinum, though it can be sometimes ambiguous, since it also refers to other species, like A. vineale or A. canadense, as well as to plants from the genus Tulbaghia (Defelice 2003; Maine Rare Plant List 2013; Lyantagaye 2011). As far as morphological features are concerned ramson is a typical representative of the Allium genus. The plant is a bulbiferous, vernal geophyte. Its bulb is narrow, elongated, about 1.56 cm long, surrounded by the layers of clear skin with only a few fibers at the base. Sometimes daughter bulbs are formed, what is important for vegetative reproduction. Contractile roots start to develop approximately from the age of three (Eggert 1992; Ernst 1979; Szafer et al. 1988; Oborny et al. 2011; Macku and Krejca 1989; Cincura et al. 1990). When the soil is soft enough to enable the roots to dwell deeper and deeper, after 10 years they can reach down the level even 27 cm lower (Ellenberg 1988). Ramson grows up to the height of 50 cm. The aerial parts of the plant consist of a triquetrous, erect, flower stem, solid in cross-section. Atop a stalk, there is a semispherical umbel-like inflorescence, which comprises of 330 starry, snowy-white flowers (according to Baz_ ewicz-Wozniak: 13.424.0 on average). They are surrounded by 23 spathal bracts until anthesis. Flower parts are in 6s sets (Eggert 1992; Ernst 1979; Berger 1960; Szafer et al. 1988; Rejewski 1996; Macku and Krejca 1989; Cincura et al. 1990; Baz_ ewicz-Wozniak et al. 2011). Ramsons blooming usually starts in April and ends in the first half of May. The plant develops 23 leaves, which are shorter than stem, smooth, flat, elliptic-lanceolate with a distinct, well-developed blade, sharpened at the apex, and gradually narrowed into petiole at the base. The width of ramson leaves is 2064 mm (Szafer et al. 1988; Ba z_ewicz-Wozniak and Michowska 2011). A comparative study on a collection of A. ursinum specimens from different ecotypes in Poland (Dukla, Roztocze, Bieszczady) showed that, they differed significantly in the width of leaf blades, the length of leaf stalks and flowering stems, the number of flowers in inflorescences (Ba z_ewicz-Wozniak and Michowska 2011). Allium ursinum regenerates mainly by seeds; vegetative regeneration is of minor importance. The seeds are black, subglobose, 23 mm wide, gathered in trichotomic capsules (Hermy et al. 1999; Sendl 1995). Mean weight per seed is 5.4 0.7 mg. They are shed in June and July, however shedding time may be delayed by weather conditions, e.g. a cold spring and summer, or north-facing aspect (Ernst 1979). Most of the seeds fall onto the ground directly beneath the capsules, but they seem to be too heavy to be moved by the wind at a ground level (Oborny et al. 2011; Ernst 1979). So, for a long-distance transport to potential growing sites the participation of animals or running water is needed (Eggert 1992). Most of the seeds remain dormant for 1 or 2 years, however, some germinate in the course of upcoming winter or spring, usually from November to March (according to Ernst it takes place from January to April) (Eggert 1992; Ernst 1979). A dense carpet of A. ursinum can produce a large number of seeds annually, even 10,000 seeds/m2 as was recorded in Gottingen Forest (Germany) (Ernst 1979). In Litovelske Pomorav (Czech Republic) floodplain forest, the mean seed production was estimated as 2,692 seeds per m2 (max 5,612 seeds/m2) (Rychnovska and Bednar 1998). Geographical distribution and habitat requirements Allium ursinum is a perennial herbaceous species, of wide-spread distribution both in Europe and Asia. Although, not growing at high altitudes (beyond 1.900 m) and in the far North (beyond ca 64 N), it can be found on natural stands from the Mediterranean region to Scandinavia (Oborny et al. 2011). It is also native to Asia Minor, the Caucasus, and Siberia, up to the Kamchatka Peninsula (Rola 2012; Madaus 1938; Oborny et al. 2011; Djurdjevic et al. 2004). Two subspecies of A. ursinum are recognized: A. ursinum ssp. ursinum and A. ursinum ssp. ucrainicum. The subdivision is based on the smoothness of pedicel surface (Karpaviciene 2006). The pedicels of the ssp. ursinum are scabrid, with numerous papillae, and rough, while the ssp. ucrainicum has smooth pedicels without papillae (Rola 2012; Farkas et al. 2012). The former is distributed in western and central Europe, whereas the latter in eastern and southeastern part of the continent (Rola 2012; Oborny et al. 2011). The distribution areas of the two subspecies can overlap what results in the existence of transitional forms. In Poland, both subspecies along with the intermediate forms, occurring at the border of the distribution ranges, were recorded (Rola 2012). In West Caucasus and Germany ssp. (...truncated)